Aged high pressure alcohol synthesis catalysts, particularly for methanol, which contain copper, suffer from a loss or substantial decrease of catalytic activity after use over an extended period of time. This degeneration of the catalyst is believed to be caused by the growth of the crystallite in the catalyst particles. A similar phenomenon has been observed in low pressure liquid phase methanol synthesis catalysts. The growth of the crystallites results primarily in a loss of active surface area, thereby decreasing the catalytic activity.
In the field of support-platinum catalysts (such as platinum-zeolite catalyst) there is a problem of agglomeration of the catalyst particles. Some approaches to remedying this problem include cascading hydrogen over the catalyst at a designated temperature and pressure and then cascading oxygen over the hydrogen-contacted catalyst at a designated temperature and pressure. See, for example, U.S. Pat. No. 4,689,312 to Le, et al. Methanol conversion catalysts, however, do not usually contain platinum or other group VIII metals. Furthermore, methanol catalysts are coprecipitates. In addition, in the case of the liquid phase methanol synthesis process, the catalysts during use are often in a liquid slurry which makes it difficult to separate from the oil in the slurry for regeneration. Furthermore, regeneration in situ, i.e., regeneration of a catalyst in the same vessel in which the catalytic process is conducted, is often dangerous since the equipment for conducting the catalytic process in many instances has not been designed to withstand the conditions required for regeneration. Accordingly, in many instances, in order to regenerate a catalyst it is necessary to transfer it from the vessel in which the catalytic reaction takes place to a different vessel for regeneration.
Therefore, there is a need for a method for regenerating copper-containing alcohol catalysts which is not only rapid and economical, but which can be conveniently and safely carried out in situ in the same vessel in which the catalytic process takes place.